Some of the handlers who worked tirelessly to give him the skills he needed were prison inmates in Maryland.

The America’s VetDogs program at the Maryland Correctional Training Center in Hagerstown, Md. is changing lives for veterans, dogs and the inmate handlers who train them.

“So I knew this was a perfect spot for me to give back, you know, and help vets that risk their lives every day for our country. So that’s why I decided to do it,” said Glenn Flanagan, an inmate handler.

The most famous alumni to date- Sully.

“I always knew he was good. He was the calmest dog I’ve ever trained,” said Rory Koerber, an inmate handler.

Koerber finished his work with Sully a year ago, but was as touched as the rest of America to see the viral photo of his former buddy, lying in front of Bush’s casket.

His first mission- complete.

“I don’t think anybody knew he was gonna go to a president. When I found out I was like yeah, that’s a pretty big accomplishment. My grandma still can’t stop bragging about it,” Koerber said.

About two dozen dogs a year follow in Sully’s paw-steps at the training center. They will learn about 40 commands in their time there, learning how to help veterans live independently.

“The inmates that are here are hand-selected for the positions that they have. So a lot of time and attention can be given to the dogs, and a lot of time and a lot of time and attention is given to the dogs,” said John Milbourne with America’s VetDogs.